JP2003233938A - Magnetic recording/reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reproduce recording-failed data by adding relatively simple circuitry without changing the circuitry of a previous stage such as a cylinder or a head amplifier, for data recorded magnetically with a rotary head on a magnetic tape in a state in which a recording track is different in inclination from a normal recording track or in a state in which bending is generated due to failures during writing. <P>SOLUTION: A circuit 104 is provided to restructure frame data by block by lowering a tape traveling speed when continuous failure of recorded data is detected by error detection or the like during reproduction, and data reproduction is carried out by using normal reproducing circuitry. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus, and more particularly to a magnetic recording / reproducing apparatus for recording / reproducing compressed or uncompressed digital data on a tape-shaped magnetic recording medium by a rotary head.

[0002]

2. Description of the Related Art As a magnetic recording / reproducing apparatus for obliquely recording a signal on a magnetic tape using a rotating cylinder,
There are a video tape recorder (VTR) device for recording a video signal and an audio signal, and a digital data storage device using a magnetic tape medium having a width of 4 mm or 8 mm as a large capacity backup device for computer data.

As a reproducing system of a data track recorded by such a device, there is a tracking reproducing system in which the reproducing head passes through the center of the recording track and the tracking information is constantly controlled by using the reproducing information of the recorded track. , There is a non-tracking reproduction method in which a reproduction operation is performed without performing tracking control.

As a non-tracking reproduction system, Japanese Patent Application Laid-Open No. 06-236505 or Japanese Patent Application Laid-Open No. 10-11
As disclosed in Japanese Patent Publication No. 2014, by providing a rotating cylinder with a plurality of reproducing heads, which is a multiple of the number of recording heads, the reproducing head scans one recording track during one rotation of the cylinder. By doing it multiple times,
A structure for obtaining a reproduction signal of a recording track is used.

As a reproduction signal processing method, for example, as shown in Japanese Patent Laid-Open No. 2001-43638, data of a plurality of channels is taken into a large capacity memory and data processing is performed on the large capacity memory in which a plurality of tracks are written. There are known methods for reconstructing track data and reproducing data.

[0006]

However, in the reproducing system in which the rotating cylinder is provided with a plurality of reproducing heads,
Since the number of reproducing heads is large, the manufacturing cost of the cylinder increases, the cost increases due to the increase in circuits accompanying the parallel processing of the reproducing circuits, and the power consumption increases due to the parallel processing.

Further, even in the above-mentioned reproduction signal processing system, a large-capacity memory is required, which causes an increase in cost. Therefore, the present invention solves such a problem and, for example, data is recorded on a tape-shaped magnetic recording medium in a state where a recording track has a different inclination or a bend from a normal recording track due to a defect during writing. In this case, the purpose is to be able to reproduce such defective recording data by adding a relatively simple circuit configuration without changing the circuit configuration of the preceding stage such as the cylinder or head amplifier. To do.

[0008]

In order to solve this problem, the present invention normally performs reproduction by tracking control, and when a track error is detected, reduces the reproduction speed to perform non-tracking reproduction. The recording frame data is reproduced by reproducing the data of the same recording frame an odd number of times, and the frame data is reproduced using the minimum frame memory for non-tracking and the error detection signal of the normal tracking reproduction circuit. By providing the circuit configuration, the tracking reproduction and the non-tracking reproduction can be realized by adding a small-scale function.

As a result, even if recording track data that cannot be tracked due to a narrower track or the like is generated, the data can be stably reproduced, so that important backup data in increasing the capacity of the magnetic tape drive can be obtained. The protection ability can be improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1 provides a magnetic recording / reproducing apparatus for recording / reproducing data by a rotary head, and means for performing tracking control so that the reproducing head passes a recording track when reproducing data. A non-tracking reproducing means for performing a reproducing operation regardless of the recording track position, and reproducing the data by the tracking control so that the reproducing head passes the recording track during the normal reproduction, and the reproducing defect due to the bending of the recording track. When is detected, the tape traveling speed is reduced to perform non-tracking reproduction in which the reproducing operation is performed regardless of the position of the recording track. This has the effect of switching to the optimum data reproduction operation depending on the state of the input data.

According to a second aspect of the present invention, there is provided a pair of recording heads for azimuth recording, and only a pair of reproducing heads corresponding to the recording heads. . This has the effect of switching between tracking reproduction and non-tracking reproduction with the same recording / reproducing head configuration as in normal tracking reproduction.

According to a third aspect of the present invention, when performing non-tracking reproduction, the rotating cylinder is configured to have the same number of rotations as in normal reproduction, and the tape running speed is 1/3, 1 or 1. / 5 ..., so that the reproduction head reproduces data a pair of recording tracks (two tracks, that is, one frame) an odd number of times (odd frames) by being configured to be an odd-numbered one compared with normal reproduction. It is configured as follows. This has the effect of increasing the reading efficiency of the reproduction data during non-tracking reproduction.

According to a fourth aspect of the present invention, a signal reproduced by a rotary head that is normally tracking-controlled is subjected to data processing in track units or frame units according to a predetermined format, and tracks are divided during non-tracking reproduction. A reproduction signal processing circuit for storing data in blocks and a frame memory for storing one frame data are provided, and during normal tracking reproduction, the reproduction signal processing circuit performs data processing for frame data. In addition to the above, during the non-tracking reproduction, the reproduction signal processing circuit is configured to store the data in the frame memory in block units. As a result, the reproduction signal processing is performed in frame units during the tracking operation, and the reproduction new word processing is performed in block units during the non-tracking operation.

According to a fifth aspect of the present invention, in a recording track, a signal of one track is divided into a plurality of blocks, and in each block, in addition to the data, a frame number and a block number are provided as header information of the block. ,
An error detection code (EDC code) is recorded, and a frame memory for storing frame data is provided.
It is provided with a means for reconstructing a plurality of reproduction signals obtained by reproducing the same recording frame as one frame data on the frame memory. This has the effect of improving the read probability of defective write data during recording.

According to a sixth aspect of the present invention, there is no error in the data to be recorded at the address on the frame memory corresponding to the block number included in the reproduction signal obtained by reproducing the recording frame, or an error included in the block data. It is provided with means for providing status information in block units, which indicates that this block is normal when it can be corrected by a correction code (ECC code). This has the effect of increasing the reliability of the block data recorded in the frame memory.

According to a seventh aspect of the present invention, there is provided means for determining whether all block data in the frame memory are reproducible data based on the status information. This has the effect of increasing the reliability of the frame data.

According to the present invention of claim 8, there is no error in the data to be recorded at the address on the frame memory corresponding to the block number included in the reproduced signal obtained by reproducing the recorded frame, or it is included in the block data. A normal tracking reproduction circuit operating unit for performing a judgment process as to whether or not the error correction code can be corrected, and the reproduction signal processing circuit uses the result of the judgment process in the normal tracking reproduction circuit operation unit to block data in the frame memory. And means for identifying whether or not to store. This has the effect of determining whether or not the block data is erroneous without adding an extra circuit.

According to a ninth aspect of the present invention, when the frame memory stores the block data including the block header in the case of performing non-tracking reproduction, it is the reproduction data as it is read from the tape. It is configured such that it can be stored with bit data of DC free code. This has the effect of eliminating the need for a data demodulation circuit during non-tracking reproduction.

According to a tenth aspect of the present invention, there is provided means for determining whether or not the data stored in the frame memory is reproducible frame data when performing non-tracking reproduction, and reproducible frame data. In some cases, by inputting the data stored in the frame memory to the normal reproduction circuit in the same reproduction timing as in the normal reproduction and in the same format as the reproduction data from the cylinder, the same signal input as the reproduction data input of the tracking control is input. And means for performing. As a result, in the non-tracking operation as well, by using a reproduction signal input equivalent to that in the tracking operation, there is an effect of downsizing the signal reproduction circuit for the non-tracking operation. (Embodiment 1) Embodiment 1 of the present invention will be described below with reference to FIG.

FIG. 2 is a diagram showing normal recording track data recorded in azimuth, recording track data when a track bend occurs, and a tracking reproducing track of the reproducing head.

In FIG. 2, the magnetic tape medium 201
The track data recorded obliquely with respect to is azimuth recorded, tracks 209, 211, and 213 are normally recorded + azimuth tracks (A tracks), and tracks 210, 212, and 214 are normally recorded-azimuth tracks. (B track). Also, track 21
Reference numerals 5 and 217 are + azimuth tracks (A tracks) recorded in a bent state due to a defect during recording, and tracks 216 are −azimuth tracks (B track) recorded in a bent state due to a defect during recording. Reference numeral 202 indicates the running direction of the tape.

During normal reproduction, the tracking control
Like the track trajectories 203, 204, 205, and 206 shown, the reproducing head orbit passes through the center of each recording track, and the track data is reproduced.

On the other hand, the irregularly curved track 215,
When the tracking control is applied to 216 and 217, the data is normally reproduced at the head of the recording track as shown in the track trajectories 207 and 208, but the recorded data deviates from the track of the reproducing head midway. Therefore, 1
The entire track data cannot be played.

Therefore, in the present invention, when such irregularly bent track data is detected at the time of error detection at the time of reproduction, the tape running speed is reduced without tracking control, and the track path 218 is set. As shown by, the number of scans of the reproducing head per track is increased. As a result, it becomes possible for the reproducing head 1 to pass through the entire track data for the data in which the track bend has occurred, and the entire track data can be reproduced.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIGS. 3 and 4. Figure 3
Are normal recording track data recorded in azimuth, recording track data when track bending occurs due to insufficient tension during recording, and non-tracking reproduction of the reproducing head when tape running speed is reduced to 1/3. It is the figure which showed the orbit.

Track data recorded obliquely on the magnetic tape medium 301 is azimuth recorded,
Tracks 311 and 313 are normally recorded + azimuth tracks (A tracks), and tracks 312 and 214 are normally recorded −azimuth tracks (B tracks).
Tracks 315 and 317 were recorded in a track bent state due to a defect during recording + azimuth track (A track), and track 316 was recorded in a track curved state due to a defect during recording-azimuth track (B track). ). Reference numeral 310 indicates the running direction of the tape.

In the case where the tape having the azimuth-recorded track data is reproduced while the traveling speed of the tape is reduced and the track is not controlled, it is considered to reduce the traveling speed of the tape to 1/2. In such a case where the tape speed is lowered, when the reproducing head happens to travel in the center of the reverse azimuth track at the time of the first reproduction, almost no data can be reproduced, and the reproduction is substantially only once. In addition, since this state continues, it may not be possible to scan the entire recording track.

Therefore, in the present invention, the tape traveling speed during non-tracking is reduced to "1 / odd" so that the reproducing head scans the recording track without the continuous scanning on the reverse azimuth track. Can be realized.

In FIG. 3, in the + azimuth track 315 where the track bending occurs, the data of the areas 318, 319 and 320 in the track 315 are reproduced by the three + azimuth reproducing head tracks 309, 307 and 305, respectively. That is, in the state where the track 315 is divided in its length direction, reproduction is performed by a separate head orbit for each divided portion. Similarly-
Azimuth Track 316-Azimuth Playhead Orbit 3
The data is reproduced by 08, 306 and 304. Three
02 and 303 show other azimuth reproducing head trajectories.

FIG. 4 shows recording track data when track bending occurs due to insufficient tension or the like during azimuth recording, and a non-tracking reproduction signal of the reproducing head when the tape running speed is reduced to 1/3. It is a figure.

Playback signals 401, 402, 403, 40
4, 405, and 406 are the reproducing head tracks 309, 308, 307, 306, 305, and 3 in FIG.
This is the total reproduction signal from 04. Further, 407 is a reproduction signal of the + azimuth recording track 315 by the track 309 of the + azimuth reproducing head, 408 is a reproduction signal of the −azimuth reproducing head track 308, −is a reproduction signal of the azimuth recording track 316, and 409 is a track 307 of the + azimuth reproducing head. + Reproduction signal of the azimuth recording track 315, 410-by the track 306 of the azimuth reproducing head-reproduction signal of the azimuth recording track 316, 411-by the track 305 of the + azimuth reproducing head + azimuth recording track 31
5 reproduction signal, 412-orbit 3 of azimuth reproduction head
04-is a reproduction signal of the azimuth recording track 316. Based on the above all reproduction signals, the reproduction data of the + azimuth track 315 in FIG. 3 is obtained by synthesizing the reproduction processing block output signals 407, 409 and 411, and the reproduction data of the −azimuth track 316 is the reproduction processing block. It is obtained by combining the output signals 408, 410, 412.

With such a configuration, even if a defective track at the time of recording is detected at the time of reproducing, it is possible to reproduce the record data, so that the reliability of reading the record data can be improved. . (Third Embodiment) A third embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a diagram showing a block configuration of a magnetic recording / reproducing apparatus according to an embodiment of the present invention and a data flow in the apparatus during non-tracking reproduction. In FIG. 1, the track data read from the rotary cylinder 101 is decoded into a digital reproduction signal through a head amplifier signal reproduction unit 102, and a digital signal is reproduced by a block data processing circuit 104 as a reproduction signal processing circuit and a tracking reproduction signal input processing unit 107. Is entered.

The data input to the tracking reproduction signal input processing unit 107 is converted into byte data through a demodulation circuit and input to the error detection / correction processing unit 105. The error detection / correction processing unit 105 performs error detection / correction (C1ECC) for each input block data, and outputs the processing result to the block data processing circuit 104 as a status flag of the block.

The block data processing circuit 104 calculates the memory address of the block to be stored in the frame memory from the frame number and the block number read from the header information of the input block data, and the error detection / correction circuit 105 calculates the memory address. If there is no error or the block data can be corrected by C1ECC based on the status flag of the block, the block header information and data are written to a predetermined address in the frame memory 103.

The number of block data written in the frame memory 103 corresponds to the error correction of the frame data (C2E
If the number of blocks that can be CC) is exceeded, the frame data is transferred to the tracking data reproduction signal input processing unit 107 via the selector 106.

In the above operation, the tape running speed is 1 /
In the case of 3, the same recording frame is reproduced three times, but if the reproduction operation is completed three times, the frame memory 1
If the number of block data written in 03 is less than the number of blocks in which frame data error correction (C2ECC) is possible, the tape running speed is sequentially reduced to 1/5, 1/7 ... By reproducing the frame data in accordance with the above, it becomes possible to reproduce the data of the recording track having a large bend. (Fourth Embodiment) A fourth embodiment of the present invention will be described below with reference to FIGS.

FIG. 5 is a diagram showing the internal structure of the block data processing circuit 104 in FIG. 1 and the flow of reproduced data when the tape running speed is 1/3. In FIG. 5, the reproduced signal from the head amplifier signal reproducing unit 102 of FIG. 1 is input to the block data processing unit 504 of the block data processing circuit 104. In the block status determination unit 503, based on the error detection / correction result status from the error detection / correction processing unit 105 corresponding to the reproduction signal, normal data that can be stored in the frame memory 103 for each reproduction signal in block units ( That is, it is determined whether the data is error-free data or data that can be corrected by C1ECC). The block data processing unit 504 calculates the storage address on the frame memory 103 based on the block header information of the fetched reproduction data, and when it is determined by the determination result of the block status determination unit 503 that the data is normal data, Is written in a predetermined address of the frame memory 103 with the same bit string as the reproduced signal (that is, a DC-free coded bit data string including a sync pattern, block header information, etc.).

When the tape running speed is 1/3 of the normal speed, writing to the frame memory 103 is performed in the area in the frame memory 103 with respect to the + azimuth track data storage area 501 and the −azimuth track data storage area 502. , 1 for each cylinder rotation
Write data 508 at a time, up to three times each,
509 and 510 will be performed. That is, 50
Reference numeral 8 represents writing of normal reproduction data during the first cylinder rotation, 509 represents writing of normal reproduction data during the second cylinder rotation, and 510 represents writing of normal reproduction data during the third cylinder rotation. .

After the data writing on the frame memory 103 is completed, when it is judged that the frame data can be normally reproduced, that is, the number of blocks written in the frame memory 103 is equal to or more than the number of C2ECC correctable blocks. In this case, the data in the frame memory 103
The frame data generation circuit 507 reads as a + azimuth track data reproduction signal 505 during non-tracking reproduction and a −azimuth track data reproduction signal 506 during non-tracking reproduction. Then, the frame data generation circuit 507 outputs the frame data as a reproduced signal after combining in the same format as the reproduced signal in synchronization with the cylinder rotation timing.

This combined reproduction signal is input to the tracking reproduction signal input section 107 at the same timing and format as the normal reproduction signal via the selector 106 in FIG. 1, and the same operation as the normal tracking reproduction operation is performed. The data is demodulated and transferred to the external host CPU 110 through the error correction processing unit 105, the buffer memory 108, and the host I / F unit 109.

[0042]

As described above, according to the magnetic recording / reproducing apparatus of the present invention, in addition to the normal tracking reproducing operation function,
The non-tracking playback operation function for relieving defective tracks such as track bends has a relatively small circuit configuration and does not affect the normal tracking playback operation.
It can be realized without changing the circuit on the front end side of the rotating cylinder, head amplifier, etc., and it is possible to reproduce the data of the recorded track where the track bending etc. has occurred due to the defect at the time of recording, thus narrow track It is possible to obtain the effect of improving the reliability of reading of recorded data such as important backup data recorded on a large-capacity magnetic recording medium at a pitch.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing track data and a track of a reproducing head during tracking reproduction.

FIG. 3 is a diagram showing recorded data in which a track bend has occurred and the orbit of a reproducing head during non-tracking reproduction.

FIG. 4 is a diagram showing an example of a reproduction signal during non-tracking reproduction.

5 is a diagram showing a configuration of a block data processing circuit and a frame memory in the device of FIG.

[Explanation of symbols]

101 rotating cylinder 103 frame memory 104 block data processing circuit 105 Error detection / correction processing unit 503 Block status determination unit 504 Block data processing unit 507 Frame data generation circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G11B 20/18 520 G11B 20/18 520Z 550 550Z 572 572B 572G 574 574A 576 576B 576Z H04N 5/7826 H04N 5 / 782 BF term (reference) 5C018 AB03 AB07 AC04 5D097 AA02 BB03 CC05 JJ11 5D101 AC05 CB10

Claims (10)

[Claims] 1. A magnetic recording / reproducing apparatus for recording / reproducing data with a rotary head, wherein a means for performing tracking control so that the reproducing head passes a recording track during data reproduction, and a reproducing operation regardless of the recording track position. It has a non-tracking reproducing means for performing data reproduction by tracking control so that the reproducing head passes through the recording track during normal reproduction, and lowers the tape running speed when a reproduction defect due to bending of the recording track is detected. A magnetic recording / reproducing apparatus configured to be switchable between performing non-tracking reproduction in which a reproducing operation is performed regardless of the position of a recording track. 2. A pair of recording heads for azimuth recording is provided, and a pair of recording heads is provided corresponding to the recording heads.
The magnetic recording / reproducing apparatus according to claim 1, comprising only a pair of reproducing heads. 3. When performing non-tracking reproduction,
The rotating cylinder equipped with a reproducing head is configured to have the same number of rotations as in normal reproduction, and the tape running speed is 1/3, 1/5 ... 3. The magnetic recording / reproducing apparatus according to claim 1, wherein the reproducing head is configured to reproduce the data from the pair of recording tracks an odd number of times. 4. Normally, a signal reproduced by a tracking-controlled rotary head is subjected to data processing in track units or frame units according to a predetermined format, and data is stored in block units dividing one track during non-tracking reproduction. A reproduction signal processing circuit for performing processing and a frame memory for storing frame data are provided, and the data processing for the frame data is performed by the reproduction signal processing circuit during normal tracking reproduction, and the reproduction is performed during non-tracking reproduction. 4. The magnetic recording / reproducing apparatus according to claim 1, wherein the signal processing circuit is configured to store data in the frame memory in block units. 5. A signal of one track is divided into a plurality of blocks on a recording track, and a frame number, a block number, and an error detection code are recorded in each block as header information of the block in addition to the data. 5. The magnetic recording according to claim 3, further comprising: a frame memory for storing frame data, and means for reconstructing a reproduction signal obtained by reproducing the same recording frame a plurality of times as one frame data on the frame memory. Playback device. 6. A case where there is no error in data recorded at an address on a frame memory corresponding to a block number included in a reproduction signal obtained by reproducing a recording frame, or when the data can be corrected by an error correction code included in the block data. 5. The method according to claim 4, further comprising means for providing status information in block units, which states that this block is normal.
The magnetic recording / reproducing apparatus described. 7. The magnetic recording / reproducing apparatus according to claim 6, further comprising means for determining whether all block data in the frame memory are reproducible data based on the status information. 8. Whether or not there is an error in the data to be recorded at the address on the frame memory corresponding to the block number included in the reproduction signal obtained by reproducing the recording frame, or it can be corrected by the error correction code included in the block data. An ordinary tracking reproduction circuit operation unit for performing a determination process and whether or not the reproduction signal processing circuit stores the block data in the frame memory based on the result of the determination process in the normal tracking reproduction circuit operation unit The magnetic recording / reproducing apparatus according to claim 4, further comprising: 9. The frame memory stores, as non-tracking reproduction, DC-free code bit data which is reproduction data read from a tape when storing block data including a block header. The magnetic recording / reproducing apparatus according to claim 4, which is configured to be possible. 10. Means for determining whether or not the data stored in the frame memory is reproducible frame data when performing non-tracking reproduction, and storing in the frame memory when the data is reproducible frame data. And a means for inputting the reproduced data to the normal reproduction circuit in the same reproduction timing as in the normal reproduction and in the same format as the reproduction data from the cylinder to perform a signal input equivalent to the reproduction data input of the tracking control. 4. The magnetic recording / reproducing apparatus according to 4.